Question

as you brake your bicycle, your velocity changes from 20 east m/s to 10 east m/s in 5 seconds. what is your acceleration?
10 m/s² west
2 m/s² east
10 m/s² east
2 m/s² west

Explanation:

Step1: Identify initial and final velocity and time

Initial velocity $v_0 = 20\ m/s$ (east), final velocity $v = 10\ m/s$ (east), time $t=5\ s$.

Step2: Use acceleration formula

The formula for acceleration is $a=\frac{v - v_0}{t}$. Substitute the values: $a=\frac{10 - 20}{5}=\frac{- 10}{5}=-2\ m/s^2$. The negative sign indicates the direction is opposite to the initial - motion direction. Since the initial motion is east - ward, the acceleration is west - ward.

Answer:

D. $2\ m/s^2$ west